Instead of using a crude axe and using it up you should use any item that extends ItemAxe decreasing its durability. If you still want to require a full crude axe you could make it need 33 points of durability (durability starts on 0, not 1), just make sure that the axe has that when crafting.

Something like this has already been implemented in the next feature release, 1.2.0

Ah, nice!